JP7162635B2 - Product inspection equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a product inspection apparatus for inspecting a product group consisting of a predetermined number of continuous products containing a predetermined number of articles, and inspecting the excess or deficiency of the number of articles contained in each product, and more particularly to an article. The present invention relates to a product inspection device capable of stably inspecting the excess or deficiency of the number of articles in a product by inexpensive means regardless of the type or mode of the product.

Patent Document 1 below discloses an invention of a weight sorter that determines whether or not the number of articles contained in a product is the regular number based on the weight of a product in which a plurality of articles are packed. . This weighing machine has a reference weight value that serves as a criterion for judgment, and upper and lower allowable weight values from the reference weight value. , it is determined that the number of articles included in the product is the regular number. Then, this weight sorter calculates an average weight value of the predetermined number of products each time a predetermined number of products determined to be acceptable are weighed, and if the average weight value differs from the reference weight value, automatically correcting the reference weight value to an average weight value;

Patent Document 2 below discloses an invention of an X-ray mass measuring device. In this X-ray mass measuring apparatus, the boundary position of the transported chain-wrapped workpiece W is detected by the boundary detector 5, and this detection signal is output to the mass integrator 11 as a boundary signal after predetermined signal processing. In addition, the line mass calculation unit 10 calculates the X-ray absorption amount absorbed by the continuous wrapping work W based on the X-ray transmission data from the X-ray detector 4, and after adding up the amount of one cycle of the line sensor, the tare part The X-ray absorption amount of the content is obtained by subtracting the X-ray absorption amount of the contents, and this is multiplied by the mass conversion factor to calculate the line mass value, which is output to the mass integration unit 11 . The mass accumulating unit 11 starts accumulating the line mass value in accordance with the input timing of the boundary signal, finishes accumulating the line mass value at the next input timing of the boundary signal, and calculates the content material amount value of the individual bag. Calculate According to the present invention, it is possible to measure the mass of each individual bag in a continuous package work that is continuously wound, and to perform an empty bag inspection and a missing item inspection in real time and continuously.

Japanese Utility Model Laid-Open No. 62-10085 JP 2013-19688 A

According to the weight sorter disclosed in Patent Document 1, although it is possible to determine whether or not the number of articles contained in the packed product is the regular number, the predetermined number of articles in the packaging material can be determined. When targeting a product group in which a predetermined number of products containing could not be inspected.

According to the X-ray mass measuring apparatus disclosed in the above-mentioned Patent Document 2, it is possible to inspect the above-described product group, that is, the continuous package workpiece for missing items. It is expensive and has the following problems. In other words, even if X-rays are used, it is effective if the product contained in the packaging material is powder or liquid in a uniform state, but if the component or material of the product is not uniform, or if the product has a complicated shape. Or, if there are circumstances such as changes in the overlapping posture of items in the packaging material, discrimination by image processing of X-ray transmission images (identification of individual items) will not be stable, and packaging will not be possible. It is not possible to accurately inspect the number of articles in the product.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the prior art, and provides a product inspection apparatus and method capable of accurately inspecting the excess or deficiency of articles contained in individual continuous products at low cost. It is intended to

The product inspection device 1 described in claim 1 is
A product group G consisting of a predetermined number of continuous products W each containing a predetermined number of articles A is weighed while being transported, and based on the measured value acquired, the excess or deficiency of the number of articles A contained in each product is inspected. A product inspection device 1,
a weighing conveyor 2 having a length on which the entire product group G can be placed;
a scale 3 for weighing the product W conveyed to the weighing conveyor 2 and outputting a weighing signal;
a sensor 4 for detecting the product W carried into the weighing conveyor 2;
a storage unit 6 for storing a weighing signal output from the scale 3 based on the timing at which the sensor 4 detects the product W;
A calculation unit that uses the weighing signal of the storage unit 6 to calculate a weighing error that is a difference between a partial weighing value that is a weight value of a part of the products W acquired by changing the measurement timing and a predetermined reference value. 8 and
an output unit 10 that outputs the weighing error in correspondence with the measurement timing;
is equipped with

The product inspection apparatus 1 according to claim 2 is the product inspection apparatus 1 according to claim 1, wherein the storage unit 6 includes at least one excess/deficiency product WB with an excess/deficiency in the number of the articles A. storing the sample weighing signal obtained from the sample product group SG;
The calculator 8 is characterized by calculating the weighing error using the sample weighing signal as the weighing signal.

The product inspection apparatus 1 according to claim 3 is the product inspection apparatus 1 according to claim 2, wherein the storage unit 6 includes at least one regular product WG in which the number of the articles A is neither excessive nor deficient. storing the sample weighing signal obtained from the sample product group SG;
The calculation unit 8 uses the sample weighing signal to calculate the weighing error for each product W of the sample product group SG,
The output unit 10 is characterized by outputting the weighing error in the sample product group SG in correspondence with the measurement timing.

The product inspection apparatus 1 according to claim 4 is the product inspection apparatus 1 according to any one of claims 1 to 3,
The calculation unit 8 divides the total weighed value corresponding to the weight of the sample product group SG consisting of n regular products WG with respect to the number of the articles A by n. It is characterized by calculating a value.

The product inspection apparatus 1 according to claim 5 is the product inspection apparatus 1 according to any one of claims 1 to 4,
The output unit 10 is characterized by displaying a graph showing the relationship between the weighing error and the measurement timing.

According to the product inspection apparatus described in claim 1, by using weighing signals obtained by weighing a group of products, partial weighing values of some products are obtained by shifting the measurement timing, and the partial weighing values are acquired. and a predetermined reference value, a weighing error can be calculated. Based on this relationship between weighing error and measurement timing, determining the measurement timing that minimizes the weighing error increases the reliability of the weight value calculated for each product when actually weighing a group of products. . Therefore, it is possible to accurately inspect the excess or deficiency of articles contained in individual products of the product group at low cost without using expensive equipment such as an X-ray inspection device.

According to the product inspection apparatus described in claim 2, since a sample product group including excess and deficiency products is used, the weighing error of the excess and deficiency products can be grasped. In addition, the threshold value for judging excess or deficiency can be appropriately set based on the measurement value of the excess or deficiency of the product, not based on the standard weight value as the production control standard of the product.

According to the product inspection device described in claim 3, a weighing error is obtained by using a sample product group that includes not only excess or deficiency products, but also regular products that are neither excess or deficiency. An intermediate value between the weighing error grasped using a group of sample products including products in excess and deficiency can be set as a threshold value, and determination of excess and deficiency can be performed with higher accuracy.

In addition, the sample weighing signal obtained from the sample product group is used to output the weighing error for each product in correspondence with the measurement timing. Timing can be used, and excess/deficiency determination can be performed with high accuracy. For example, if the number of items included in one product is small, even if one or two items are missing, the impact on the weighing value of one product is large, so the calculated weighing error will be large. Therefore, it is relatively easy to accurately determine whether the number of items in each product is too much or too little based only on the relationship between the weighing error and the measurement timing. However, when the number of items contained in one product is large, even if there are missing items, if the number of missing items is small, the decrease in the weight value of one product is small, and the calculated measurement error is Since it tends to be smaller, it is relatively difficult to judge whether the number of items in each product is too much or too little. In such a case, even if a preferable measurement timing range is determined from the relationship between weighing error and measurement timing, within that range of measurement timing, variations in the position of the items included in the excess or deficiency product will cause a weighing error. may fall within the threshold.

However, according to the product inspection apparatus described in claim 3, after determining the preferable measurement timing based on the relationship between the weighing error and the measurement timing of the regular product that is neither excessive nor deficient, the product that is excessive or insufficient is determined. Based on the relationship between weighing error and measurement timing, the range of measurement timing in which excess or deficiency products fall within the threshold is excluded from the previously determined preferred measurement timing, so that only regular products with no excess or deficiency are found. The best measurement timing can be determined such that the weighing error is within the threshold for .

According to the product inspection device described in claim 4, when the number of products constituting the product group is generalized to n, it corresponds to the weight of the regular sample product group consisting of n full regular products. By calculating the reference value based on the value obtained by dividing the total weighed value by n, the nth product is calculated from the reference value and the partial weighed value which is the weight value of the nth product W Such weighing errors can be calculated.

According to the product inspection apparatus described in claim 5, when determining a preferable measurement timing that reduces the weighing error calculated from the weighing signal, a graph showing the relationship between the weighing error and the measurement timing is displayed on the display unit. can do. Therefore, it is possible to easily visually recognize the preferable measurement timing that reduces the weighing error of the product group, which contributes to the simplification of the measurement timing setting work.

It is a lineblock diagram of a product inspection device of a 1st embodiment. FIG. 4 is a diagram showing a waveform of a weighing signal output by a scale that measures a group of products in double packages in the product inspection apparatus of the first embodiment, as being shaped by a filter. 7 is a graph showing the relationship between the measurement timing and the weighing error calculated by the calculator from the weighing signal of the regular product group and the weighing signal of the excess/deficiency product group, respectively, in the product inspection apparatus of the first embodiment. 9 is a graph showing the relationship between measurement timing and weighing error calculated by a calculator from the weighing signal of the regular product group and the weighing signal of the excess/deficiency product group, respectively, in the product inspection apparatus of the second embodiment. FIG. 10 is a diagram showing a waveform of a weighing signal output by a scale that measures a group of three-packaged products in the product inspection apparatus of the third embodiment, as being shaped by a filter.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.
The product inspection apparatus 1 of the first embodiment shown in FIG. 1 is intended for a product group G composed of two connected products W shown in the upper part of the figure. FIG. 1 shows a situation in which a group of products G conveyed by the preceding conveying means CV is sequentially carried into the product inspection apparatus 1 .

A product group G shown in FIG. 1 includes two products W containing a predetermined number of articles A in packaging materials, and the two products W are connected at a part of the packaging material P. As shown in FIG. Here, the product W on the front in the conveying direction is called the front product WF, and the product W on the rear in the conveying direction is called the rear product WR. Connection means that a part of each product W (the packaging material P in this case) is connected to each other. The two products W (WF, WR) that make up product group G are manufactured using product group G as a single unit. Even if the items are the same, there are cases where an item A that should be included in one product W may be included in the other product W, and the number of products W may be in excess or deficiency, so it is necessary to inspect this. .

In such an inspection of the excess or deficiency of the number of articles A in the product group G, it is not possible to detect the excess or deficiency of the number of articles A even if the weight of the product group G is measured. According to the product inspection apparatus 1 and method of the first embodiment, it is possible to accurately inspect the excess or deficiency of the number of articles A in the individual products W constituting the product group G at low cost.

As shown in FIG. 1, the product inspection apparatus 1 of the first embodiment includes a weighing conveyor 2 having a length sufficient for placing the entire product group G, a scale 3 supporting the weighing conveyor 2, and a product group. It has a sensor 4 for detecting G and a control means 5 for controlling the entire product inspection apparatus 1 and determining the excess or deficiency of the articles A contained in each product W of the product group G.

In the example shown in FIG. 1, the scale 3 weighs two products W (WF, WR) belonging to one product group G while conveying them on the weighing conveyor 2, and outputs weighing signals as shown in FIG. The waveform of the weighing signal shown in FIG. 2 is not the waveform itself of the weighing signal output from the scale 3, but the waveform shaped by the filter of the signal processing unit 7, which will be described later. In this first embodiment, the product group G consists of two products W (WF, WR), so as can be understood from FIG. The weighing value M1 weighed when the (counterparty product WF) is placed on the weighing conveyor 2 (time t1), and when the weighing conveyor 2 is conveying two products W (WF, WR) (time t2) ) contains the weighing value M2 of the two products W weighed.
Hereinafter, the weight value of a part of the products W in the product group G will be referred to as "partial weighing value", and the weight value of the entire product group G will be referred to as "total weighing value".

Although not indicated by reference numerals in the graph of FIG. 2, the weighing signal includes one product W from the other party (the Since the weight value of one product W (rear product WR) weighed at the rear of the product WF) descended from the weighing conveyor 2 is included, this weight value may be used. The weighing value of the rear product WR is the "partial weighing value" described above. As shown in FIG. 1, a weighing signal from the scale 3 is input to the control means 5 and stored in the storage section 6 .

As shown in FIG. 1, the sensor 4 is provided at the carry-in position where the product group G is carried onto the weighing conveyor 2, detects the passage of the product group G, and outputs a detection signal. As shown in FIG. 1, the detection signal from the sensor 4 is input to the control means 5 and used to determine the timing for calculating the weight values M1, M2, etc., from the weighing signal output from the scale 3.

As shown in FIG. 1, the control unit 5 includes a signal processing unit 7, a calculation unit 8, an excess/deficiency determination unit 9, a display unit 10, and an operation unit 11 in addition to the storage unit 6 described above.

The signal processing unit 7 is a means for performing necessary filter processing on the weighing signal for a required time period in order to calculate a weighing value using the weighing signal stored in the storage unit 6. A weighing signal is sent to the calculator 8 .

The calculation unit 8 calculates the timing when the sensor 4 detects the product group G, the loading time T1 required for the product W to be loaded onto the weighing conveyor 2, and the state of the scale after the product W is loaded onto the weighing conveyor 2. In consideration of the stabilization time T2 until the is stabilized, the measurement timing T (corresponding to the times t1 and t2) preferable for calculating the weighing value is determined, and the weighing value M1 corresponding to the product W on the weighing conveyor 2 is determined. , M2, etc. are calculated from the weighing signal processed by the signal processing unit 7. FIG. Of these measured values, the measured value M1 indicates the weight of the former product WF, and the measured value M2 indicates the total weight of the former product WF and the later product WR. Therefore, the calculation unit 8 can set the measured value M1 as the weight value of the forward product WF, and the value obtained by subtracting the measured value M1 from the measured value M2 as the weight value of the backward product WR.

If the measured value of the backward product WR is acquired when the destination product WF descends from the weighing conveyor 2, this is taken as the weight value of the backward product WR, and the value obtained by subtracting the measured value of the backward product WR from the measured value M2. can also be taken as the weight value of the front product WF.

Furthermore, first, the supplier product WF of the product group G is weighed, and then the supplier product WF and the rear product WR are weighed. , more accurate weight values of the forward product WF and backward product WR can be obtained by calculating the average value using these three measured values.

The excess/deficiency determination unit 9 receives the weight data of one item A included in the target product W and the data of the regular number of items A included in the target product W (regular quantity). owns These data can be input from the operation unit 11 . The excess/deficiency determination unit 9 divides the weight of each product W sent from the calculation unit 8 by the weight of one item A to calculate the number of items A included in the product W. Then, the excess/deficiency determining unit 9 determines whether or not the weight of each product W is within an allowable range set based on the value obtained by multiplying the weight of one article A by the normal quantity. , and the result is displayed on the display unit 10 . Specifically, for each of the former product WF or the later product WR, the actual number of items A, the regular quantity, the difference (weight) between the number of products A and the weight corresponding to the regular quantity, and the pass/fail The judgment is displayed on the display unit 10 .

As described above, according to the product inspection apparatus 1 of the first embodiment, the weight of each product W is calculated by calculation using the partial weighing value and the total weighing value, and the number of articles A contained in each product W is calculated. can be inspected for excess or deficiency.

However, even if the measurement of a total weight such as weight M2 is relatively stable compared to the measurement of partial weights since all products W are on the weigh conveyor 2, the weight M1 In order to accurately calculate such a partial weighing value, it is necessary to appropriately set the measurement timing T (corresponding to the time t1) preferable for calculating the partial weighing value. As described above, the measurement timing T consists of the loading time T1 required for the product W to be loaded onto the weighing conveyor 2 and the time required for the balance to stabilize after the product W has been loaded onto the weighing conveyor 2. Although it is determined in consideration of the stabilization time T2, it is not necessarily easy to set the optimum measurement timing T by assessing each of these times T1 and T2. If the measurement timing T is not appropriate, the calculation error increases, the reliability of the weight value obtained for each individual product W decreases, and as a result, the number of articles A included in each product W in the product group G decreases. Excessive or deficient test results also reduce reliability.

Therefore, the product inspection apparatus 1 of the first embodiment has a configuration for appropriately setting the measurement timing T for calculating the partial weighing value.
When actually inspecting a certain product group G using the product inspection apparatus 1 of the first embodiment, prior to the actual measurement of the product group G, work and settings for appropriately setting the measurement timing T are performed. do First, a regular product group GG, which is a product group G composed of regular products WG in which the number of articles A included in each product W is neither excessive nor deficient, is used as a sample product group SG. This regular product group GG is weighed while being conveyed by the weighing conveyor 2, and a weighing signal as shown in FIG. The calculation unit 8 performs the following calculation using the weighing signal in the storage unit 6 processed by the signal processing unit 7 .

The calculation unit 8 varies the time t1 of the weighing signal corresponding to the measurement timing T of the weighing value within an appropriate range on the time axis, and calculates the weighing value M1, which is the partial weighing value, at each time t that has been varied. do. Further, an operation (M2-M1) is performed to subtract the weight value M1, which is a partial weight value, from the weight value M2, which is a total weight value, to calculate a plurality of operation results. The weight value (M2-M1) obtained by subtracting the weight value M1, which is the partial weight value, from the total weight value corresponds to the weight value of the backward product WR.

In this embodiment, the predetermined reference value is the standard weight of the regular product WG, but if the reference value is 0 g, the weighing error will be the same value as the weight value obtained by weighing. In this way, the reference value may be a standard weight value determined by the production control standards of the regular product WG, a regular weight value obtained by actually weighing the regular product WG, or a plurality of regular weight values. may be the average value of In addition, when the normal weight value is used, the value of the packaging material can also be taken into consideration as the tare.

Then, the calculation unit 8 performs an operation of subtracting the reference value from the partial measurement value M1 for each measurement value M1. This calculation result is called a "weighing error" (indicated by symbol E). Accordingly, the weighing error E is acquired at each variable number of times t1 corresponding to the measurement timing T. FIG. The weighing error E is the difference between the weighed value for one product W and the reference value.

FIG. 3 shows the relationship between the weighing error E (vertical axis) and the measurement timing T (horizontal axis) related to the weighing value M1, which is the partial weighing value, calculated from the weighing signal of the regular product group GG as described above. It is a graph FG showing. When the calculation unit 8 calculates the weighing error E and acquires the graph FG, the data is sent to the display unit 10 and displayed. The vertical axis of the graph FG displays a threshold as a value defining an allowable range for judging whether the number of articles is excessive or deficient. This threshold value is set in consideration of the variation in weight allowed for the products W in the product group G. That is, since the weight of the article A contained in the product W varies, the weight of each product W is not necessarily the same, but there is a limit to allow the product W to be a genuine product even if the weight is not the same. The threshold is set in consideration of this. In this first embodiment, assuming that the standard weight value of the article A contained in the product W is 4 g according to the production control standard, a specific example of the threshold value is 5 g, which is slightly heavier than this (here, for simplicity, absolute 5 g as a value, but not limited thereto). A threshold is set from the operation unit 11 .

FIG. 3 shows a graph FB obtained by calculation at a plurality of timings from the weighing signals of the excess/deficiency product group GB and a graph FG obtained from the weighing signals of the regular product group GG on the same coordinate plane. , the weighing error E corresponding to a product W in the product group G forms a trough at approximately the same measurement timing T0. When this graph FB has the shape shown in the figure, if the weighing error E stabilizes at the bottom of a valley near T0, or if there is no valley and stabilizes in a gentle range of slope, then the weighing error EB is grasped. Assuming that this weighing error EB is 7 g, and considering variations, a threshold value of 6 g or 5 g, which is slightly smaller than this, is set. Judging that it is adequately accommodated.

That is, even if it is not clear whether the weighing error EB corresponds to the weight of one item A, the threshold value can be determined by grasping the weighing error E from the weighing signal for the product W that actually has one excess or deficiency. It is not necessary to obtain the exact weight of the product W in order to determine the excess or deficiency of the stored items A.

On the other hand, regarding the fact that it is not necessary to obtain an accurate weight of the product W, it may not be certain that the weighing error E when the product W is weighed in just the right amount is 0g (±0g). For this, the graph FG shown in FIG. 3 is used. That is, the weighing error E is grasped from the weighing signal of the product W that is neither excessive nor deficient, and based on the relationship with the weighing error EB of the product W that is excessive or deficient, a highly reliable threshold value is set for judging excess or deficient. can.

If the graph FG obtained from the weighing signal of the regular product group GG yields the proper weighing error E for the regular product WG (the minimum value of 1 g in the example shown above), the above-described threshold value of 6 g or 5 g is obtained. In addition to being able to understand that it is appropriate between 1 g and 7 g, the midpoint (4 g in this specific example) between the minimum value of the weighing error of the regular product group GG and the weighing error EB of the above-mentioned excess and deficiency product group GB A threshold value can also be used, and excess/deficiency can be determined more accurately.

Once the threshold value for judging the excess/shortage of the article A for the product W is determined, the range of the measurement timing T in which the excess/shortage can be judged with high reliability can be grasped by this threshold value. That is, the measurement timing T is set so that the weighing error E of the product W that is neither excessive nor deficient is less than the threshold value, and that the weighing error E of the product W that is excessive or deficient is equal to or greater than the threshold value.

According to the graph FG shown in FIG. 3, within the range TG1 of the measurement timing T where the weighing error E is below the threshold, the measurement timing T can be set so that the variation in the weight of each product W is less than the threshold 5 g. can. For example, in the graph FG, the measurement timing T0 at which the weighing error E is the minimum value of 1 g may be determined as the measurement timing T of the weighed value M1 during inspection. Even if the measurement timing T0 cannot be set, the measurement timing T can be set to a stable point within the range TG1 where the variation of the weighing error E is small. By setting the measurement timing T in this way, the reliability of the weight value of each product W obtained by calculation using the measured value M1 and the measured value M2 is ensured. Reliability is also ensured for the inspection of the excess or deficiency of the number of articles A to be delivered.

A preferable measurement timing T of the metric value M1 may be visually recognized by the user who sees the graph FG displayed on the display unit 10, and may be input and set from the operation unit 11 so that it becomes effective in subsequent examinations. and may be set automatically.

The method using the graph FG showing the relationship between the weighing error E and the measurement timing T has been described above with reference to FIG. However, a modification of this technique will now be described. In the above-described method, the regular product group GG is used as the sample product group SG, but in the modified example, the excess/deficiency product group GB is used as the sample product group SG to grasp the weighing error of the excess/deficiency product WB. . The excess/deficiency product group GB is a product group G including at least one excess/deficiency product WB.

According to this modification, the threshold value (5 g as a specific example in FIG. 3) for judging the excess or deficiency of the article A in the product W is not based on the standard weight value as the production control standard of the product. A more appropriate threshold value can be set based on the weight value M1 of the product W containing an excess or deficiency of the number of articles A. In general, in order to determine a product W with one item A in excess or deficiency, a threshold value is set based on the weight of one item A, but accurate measurement of the weight itself is essential in the first place. Assuming that it is difficult, from the viewpoint of how to accurately determine the excess or deficiency, that is, to determine the excess or deficiency product WB and the regular product WG without error, the weight of one article A contained in the product W is not necessarily the threshold value. It is not always appropriate to do so.

Specifically, even if the regular product WG is supposed to be 20 g, the measurement result may not always be 20 g due to the influence of the products W before and after (especially when they are connected). Similarly, in the measurement of product W, which should be 20g if it is a regular product WG, one item A is 4g, so even if the threshold is set to ±4g, product W with excess or deficiency of item A is actually measured. It is unknown whether the weight actually becomes, for example, 16 g or 24 g when the measured value is measured.

Furthermore, in this modified example, if a plurality of data are obtained for both the excess/deficiency product WG and the regular product WG, the variation in the weighing error E can be grasped for both, so the reliability of the threshold value set based on this can be further improved. do.

As described above, according to the product inspection apparatus 1 of the first embodiment, from the weighing signal of the product group G, a plurality of partial weighing values are calculated by varying the measurement timing T, and the partial weighing values and the predetermined A plurality of weighing errors E can be calculated as the difference from the reference value. Based on the relationship between these multiple weighing errors E and measurement timing T (Fig. 3), if the measurement timing T is determined so that the weighing error E is less than the threshold, when the product group G is actually weighed, the product The weight values obtained for each W are more reliable. Therefore, the effect of being able to accurately inspect the excess or deficiency of items contained in individual products in the product group at low cost can be reliably obtained without using expensive equipment such as an X-ray inspection device.

In addition, when determining such a preferable measurement timing, a graph showing the relationship between the measurement error E and the measurement timing T is displayed on the display unit 10 so that the measurement timing T can be easily recognized visually. Even if the measurement timing T is set manually, the work becomes easy.

Next, a second embodiment will be described with reference to FIG.
The configuration of the product inspection apparatus of the second embodiment is the same as that of the first embodiment, but the method of setting the measurement timing T of the partial weighing value is slightly different from that of the first embodiment. , the description of the first embodiment is used for other parts.

As in the first embodiment, even if the preferred range of the measurement timing T of the partial weighing value is specifically determined from the relationship between the weighing error E obtained from the weighing signal of the regular product group GG and the measurement timing T, the product A When the target is a surplus/deficiency product group GB including products W with an excess or deficiency in the number of , there is a possibility that the weighing error E of the products W in the excess/deficiency product group GB will be less than the threshold.

For example, if the regular number of items A included in one product W is small, even if one or two items are missing, the effect on the weighing value of the product W is large. Since the error E becomes large, it is relatively easy to accurately determine the excess or deficiency of the number of articles A in each product W based only on the relationship between the measurement error E of the regular product group GG and the measurement timing T.

However, if the regular number of articles A included in one product W is large, even if there are missing items, if the number is small, such as one or two, the weighing of the product W Since the decrease in value is small and the calculated weighing error tends to be small, it becomes relatively difficult to judge whether the number of articles A in each product W is excessive or insufficient.

In such a case, even if a preferable measurement timing T range is determined from the relationship between the weighing error E of the regular product group GG and the measurement timing T (Fig. 3), the Due to the influence of variations in the position of the article A, the weighing error E obtained from the weighing signal of the excess/deficiency product group GB may fall within the allowable range. For example, in a product W with a large excess or deficiency such as two to three items A, the storage position of the items A may be biased, and the weighing error E may not form a trough at the measurement timing T0. be.

Therefore, in the second embodiment, after determining the preferable measurement timing T, the relationship between the weighing error E and the measurement timing T is obtained for the excess/deficiency product group GB with different excess/deficiency numbers, and both graphs are displayed on the display unit 10. to correct the setting of the preferable measurement timing T.

FIG. 4 shows graph FG shown in FIG. 3 and graph FB obtained for surplus/deficit product group GB including product W in which two articles A are in excess based on the same weighing and calculation as graph FG. , superimposed as a graph on one coordinate axis. This graph is also displayed on the display unit 10 .

In the graphs FG and FB shown in FIG. 4, the range of measurement timings T in which the weighing error E of the graph FB is less than the threshold value is removed from the range TG1 of the measurement timings T described above, and the range TG2 of the corrected preferable measurement timings T is removed. and

In FIG. 4, within the range TG1 of the measurement timing T, in the region X where the weighing error E of the graph FB exceeds the threshold, the weighing error E of the excess/deficiency product group GB exceeds the permissible variation in the weight values of the products W. Therefore, it can be detected that the product W is defective. However, in the area Y where the weighing error E of the graph FB is below the threshold, the weighing error E of the excess/deficiency product group GB is smaller than the permissible variation in the weight value of the product W. indistinguishable from Therefore, this region Y of the measurement timing T is excluded from the preferable range TG1 of the measurement timing T set based on the regular product group GG.

In the second embodiment, the measurement timing T may be set within the range TG2. For example, the measurement timing T0 at which the weighing error E is the minimum value of 1 g in the graph FG is determined as the measurement timing T of the weighed value M1 during inspection. Just do it. According to the measurement timing T thus set, since the measurement error E of the product W of the regular product group GG falls within the allowable range, it is possible to judge non-defective products as non-defective products. , can be reliably identified from the product W of the regular product group GG.

Next, a third embodiment will be described with reference to FIG.
The configuration of the product inspection apparatus of the third embodiment is the same as that of the first embodiment, but the configuration of the target product group G is different. and the description of the second embodiment.

A product group G in the third embodiment includes three products W each containing a predetermined number of articles A in a packaging material P, and the three products W are connected at a part of the packaging material. Here, the product W at the front in the conveying direction is called the front product WF, the intermediate product W in the conveying direction is called the intermediate product WM, and the product W at the rear in the conveying direction is called the rear product WR.

In the example shown in FIG. 5, the scale 3 weighs three products W (WF, WM, WR) belonging to one product group G while conveying them on the weighing conveyor 2, and outputs weighing signals as shown in FIG. do. The waveform of the weighing signal shown in FIG. 5 is not the waveform itself of the weighing signal output from the scale 3, but the waveform shaped by the filter of the signal processing unit 7. As shown in FIG. In the third embodiment, the product group G consists of three products W (WF, WM, WR), so as can be seen from FIG. The weight value M1 weighed when W (counterparty product WF) was placed on the weighing conveyor 2 (time t1), and when two products W (WF, WM) were placed on the weighing conveyor 2 (time t2 ) and the three products W weighed when the three products W (WF, WM, WR) were placed on the weighing conveyor 2 (time t3) contains a metric M3 of .

Although not indicated by reference numerals in the graph of FIG. 5, the weighing signal includes two parts where the weighing value after time t3 is substantially constant. The weighing values of the two products W (WM, WR) at the back, which were weighed when the product WF) descended from the weighing conveyor 2, and the two products W (WF, WM) descending from the weighing conveyor 2 Since the weight value of the one rear product W (rear product WR) weighed at the same time is included, these weight values may be used.

The inspection method for excess or deficiency of the number of articles A in each product W in the third embodiment is the same as in the first embodiment. That is, the weights of the destination product WF, the intermediate product WM, and the backward product WR are calculated by calculation using the reference values calculated from the weight values M1 and M2, which are the partial weight values, and the weight value M3, which is the total weight value, and The number of articles A contained in each product W is obtained, and the excess or deficiency thereof is determined.

In the third embodiment, similarly to the first embodiment, in order to appropriately determine whether the number of items A included in the product W is excessive or insufficient, the partial weighing values (measurement values M1 and M2) are appropriately obtained from the weighing signal. For the calculation, it is necessary to appropriately set the measurement timings T of the partial weight values (weight values M1 and M2). Therefore, in the third embodiment, which targets a product group G consisting of three products WF, WM, and WR, the weighing error E required to preferably determine the measurement timing of the two partial weighing values is calculated as follows. Calculated by formula.

Weighing error EF = (M1) - (M3/3) for the product of the other party WF = (1)
Weighing error EM for intermediate product WM=(M2-M1)-(M3/3) Equation (2)
The above formula (2) for calculating the weighing error EM related to the intermediate product WM may be (M2/2)-(M3/3).

That is, in order to calculate the weighing error EF related to the product WF of the other party, the calculator 8 varies the time t1 of the weighing signal, which corresponds to the measurement timing T of the weighing value, within an appropriate range on the time axis. A plurality of metric values M1, which are partial metric values, are calculated. Then, as shown in equation (1), the weight value M3, which is the total weight value, is divided by 3, which is the number of products W, to obtain the weight value of one product W, which is used as a reference value. The reference value is subtracted from the measured value M1, which is a value, to calculate the weighing error EF related to the destination product WF. Then, the relationship between the calculated weighing error EF and the measurement timing T is shown in a graph similar to FIG. 3, and the most suitable measurement timing T for calculating the weighing value M1, which is the partial weighing value, is set.

Further, in order to calculate the weighing error EM related to the intermediate product WM, the calculator 8 varies the time t2 of the weighing signal corresponding to the measurement timing T of the weighing value within an appropriate range on the time axis. A plurality of measured values M2 are calculated. Then, as shown in equation (2), the weight value M3, which is the total weight value, is divided by 3, which is the number of products W, to obtain the weight value of one product W, which is used as a reference value. The weight value of the intermediate product WM is obtained by subtracting the partial weighing value M1 from the weighing value M2 of the intermediate product WM. Compute EF. Then, the relationship between the calculated weighing error EF and the measurement timing T is shown in a graph similar to FIG. 3, and the most suitable measurement timing T for calculating the weighing value M1, which is the partial weighing value, is set.

As described above, according to the product inspection apparatus 1 of the third embodiment, when the product group G is weighed, the reliability of the weight value obtained for each product W increases as in the case of the first embodiment. Without using expensive equipment such as an X-ray inspection device, it is possible to obtain the effect of accurately inspecting the excess or deficiency of articles contained in individual products in the product group at low cost. Also in the third embodiment, the appropriate range of the measurement timing T may be corrected in advance using the products W of the excess/deficiency product group GB. As for the reference value, a standard weight value or the like determined by the production control standards of the regular product WG may be used as in the first embodiment.

Next, a fourth embodiment will be described.
The configuration of the product inspection apparatus 1 of the fourth embodiment is the same as that of the first embodiment, but the number of products W in the target product group G is generalized to n. The product inspection apparatus 1 weighs the product group G with the scale 3 while conveying the product group G with the weighing conveyor 2, and stores the obtained weighing signal in the storage unit 6. FIG. Then, in this weighing signal, the calculating unit 8 calculates the measurement timing of the partial weighing value each time the 1st to (n−1)th products W are placed on the weighing conveyor 2 and each time the partial weighing value is measured. By varying T, a plurality of weighing errors E are calculated for each partial weighing value according to the following equation.

The calculation method of the weighing error E for the product group G in which the number of products W is n will be explained according to the following symbols and notation.
[Quantity]
Total number of products W: n
Number of products W: m (<n)
[Weighing value]
Weighing value (partial weighing value) of first product W in product group G: M1
Weighing value (partial weighing value) of product W up to second in product group G: M2
Weighing value (partial weighing value) of product W up to m-th item in product group G: Mm
Overall weight value of product group G (total weight value): Mn
[Weighing error]
Weighing error for the first product W: E1
Weighing error for the second product W: E2
Weighing error for the m-th product W: Em

According to the above symbols and notation, each weighing error E calculated at the measurement timing T when each of the 1st to mth products is placed on the weighing conveyor 2 can be expressed by the following equation. be done.
Weighing error E1 = M1 - (Mn/n)
Weighing error E2 = (M2 - M1) - (Mn/n)
…
Weighing error Em = (Mm-M(m-1))-(Mn/n)
…
The first term of the above arithmetic expression is a term representing the weight value of some products by partial weighing values or computation based on partial weighing values. That is, the weighing error Em of the m-th product W is obtained by subtracting the weighing value of the up to (m-1)th product W from the weighing value of up to the m-th product W. The second term of the above formula is a term indicating the average value of the weight values of the products obtained by dividing the total weight value Mn and the total number n, as a predetermined reference value.

The calculation unit 8 calculates a plurality of weighing errors E by varying the measurement timing T each time each partial weighing value is measured after the 1st to (n−1)th products W are placed on the weighing conveyor 2. 2 or 5 can be acquired at each measurement timing T of each partial weight value. Therefore, if the measurement timing T is determined such that the measurement error E is less than the threshold based on the relationship between the plurality of measurement errors E and the measurement timing T, when the product group G is actually weighed, the first As with the first embodiment, the weight value obtained for each product W is more reliable. Therefore, the effect of being able to accurately inspect the excess or deficiency of items contained in individual products of the product group at low cost can be reliably obtained without using expensive equipment such as an X-ray inspection device.

As described above, according to the fourth embodiment, even if the number of products W constituting the product group G is generalized to n , the weight value for each product W obtained from the partial weight values Then, the weighing error for the m (<n)th product W can be stably calculated by a simple calculation from the weighing value for each product W obtained from the outside weighing value.

In each of the embodiments described above, the target product group G is a so-called continuous package product in which a plurality of products W are connected by a part of the packaging material P. However, even a product group in which a plurality of groups are continuously formed can be the object of the present invention.

DESCRIPTION OF SYMBOLS 1... Product inspection apparatus 2... Weighing conveyor 3... Scale 4... Sensor 5... Control means 6... Signal processing part which is a filter setting means 7... Weighing part 8... Calculation part 9... Excess/deficiency determination part A... Article W... Product WF...Front product WM...Intermediate product WR...Back product WG...Regular product WB...Excess/deficiency product G...Product group GG...Regular product group GB...Excess/deficiency product group M...Weighing value E...Weighing error T...Measurement timing P... packaging material

Claims (5)

The number of articles contained in each product based on the weight value obtained by weighing while transporting a product group (G) in which a prescribed number of products (W) containing a prescribed number of articles (A) are continuously weighed. A product inspection device (1) for inspecting excess and deficiency,
a weighing conveyor (2) having a length on which the entire product group is placed;
a scale (3) for weighing the product conveyed to the weighing conveyor and outputting a weighing signal;
a sensor (4) for detecting products carried into the weighing conveyor;
a storage unit (6) for storing a weighing signal output from the scale based on the timing at which the sensor detects the product;
A calculation unit (8 )When,
an output unit (10) that outputs the weighing error in correspondence with the measurement timing;
A product inspection device (1) comprising: The storage unit (6) stores a sample weighing signal obtained from a sample product group (SG) including at least one excess or deficiency product (WB) with an excess or deficiency in the number of the articles (A),
The product inspection device (1) according to claim 1, wherein the calculator (8) uses the sample weighing signal as the weighing signal to calculate the weighing error. The storage unit (6) stores a sample weighing signal obtained from the sample product group (SG) including at least one regular product (WG) that does not have excess or deficiency in the number of the articles (A),
The calculation unit (8) uses the sample weighing signal to calculate the weighing error for each product of the sample product group,
3. The product inspection apparatus (1) according to claim 2, wherein the output unit (10) outputs the weighing error in the sample product group in correspondence with the measurement timing. The calculation unit (8) divides the total weighed value corresponding to the weight of a sample product group (SG) consisting of n regular products (WG) that are neither excessive nor deficient in the number of the articles (A) by n. A product inspection device (1) according to any one of claims 1 to 3, characterized in that said reference value is calculated based on the obtained value. The product inspection device (1) according to any one of claims 1 to 4, wherein the output section displays a graph showing the relationship between the weighing error and the measurement timing.

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